1. Field of Invention
The present invention relates generally to bridges and tailpieces for stringed instruments, and more particularly to bridges for guitars known as Tune-o-matic style bridges, and tailpieces designed for use therewith, and similar designs, which are typically mounted on adjustable posts or studs that are screwed or mounted into the guitar body.
2. Description of Related Art
Some stringed instruments, such as some electric guitars, use a style of bridge and tailpiece in which each is connected to the instrument's body via two threaded bridge or tailpiece posts (respectively) that are screwed or secured directly into the top of the stringed instrument body. In the case of the bridge, it rests on two knurled nuts or adjustment wheels that allow for the height of the bridge to be adjusted. In the case of the tailpiece, slots at each end of the tailpiece rest within a circumferential groove on the tailpiece posts. This type of bridge is commonly referred to in the industry as a Tune-o-matic bridge. Also, other stringed instruments with arched tops such as mandolins, bouzoukis and hollow-body electric/acoustic guitars with arched tops and backs (such as jazz guitars) use a similar style bridge and tailpiece.
FIG. 1 shows an exemplary top view of a Tune-o-matic style guitar bridge 10 as it would be typically mounted on a guitar body 12, together with a tailpiece 14. The tailpiece 14 holds one end of strings 16 and provides the mechanical strength for the tension of the stretched strings against the body of the guitar. The strings 16 then pass over the bridge 10, and in the case of an electric stringed instrument or guitar, the strings 16 will also pass over one or more pickups and then pass over the neck of the instrument and over a nut to the tuning pegs or machine heads.
Typically, a Tune-o-matic style guitar bridge 10 comprises an elongate base piece or bar 18 that is typically formed of metal, such as steel or brass. A top surface 20 of the bar 18 is generally flat, while the opposite bottom surface is generally concave to match the curvature of a guitar. Cut or formed in the bar 18 are several square or rectangular holes 24 extending from the top surface 20 through the bottom surface. In each of the square or rectangular holes 24 is movably mounted a saddle 26 that supports the strings 16 and that is adjustable longitudinally in relation to the strings by means of an adjustment screw. Vertically through each end of the bar 18 are vertical alignment holes 28 extending from the top surface 20 to the bottom surface. A pair of adjustable metal bridge posts 32 comprising of a partially or completely threaded post member 34 on which is mounted an adjustment wheel 36 having a complementary threaded central hole. The top portion of the post member 34 is sized to fit within vertical alignment holes 28. The most common of Tune-o-matic style bridges use either a 4 mm or 6 mm diameter vertical alignment holes 28. The lower portion of the bridge post 32 is fixedly mounted in the guitar body in a configuration such that the post members 34 align with the two vertical alignment holes 28 in the bar 18. In a conventional Tune-o-matic style bridge the bar 18 rests upon the adjustment wheel 36 such that the post members 34 are received within vertical alignment holes 28. Adjustment wheels 36 on each adjustment post 32 are either raised or lowered to achieve a desired height of the bar 18.
Typically, the tailpiece 14 comprises an elongate base piece 40 that is formed of metal, such as steel or brass. A top 42 and an opposite bottom surfaces of the tailpiece 14 are generally curved in order to aesthetically match the surface curve of a guitar upon which the tailpiece 14 is to be mounted. Several string holes traverse the base piece 40 and are generally evenly spaced apart along the length of the tailpiece 14, are formed or machined through the tailpiece 14. These string holes also have chamfered edges or indentations of a slightly larger diameter on both the front and rear entries of the string holes to accommodate small balls which are manufactured at the ends of steel strings used in some guitars. The strings are placed through the string holes towards the bridge 14 and nut of the instrument, not shown. It is the balls on the ends of the strings which act as stops and absorb the tension on the strings after top ends of the strings are mounted on tuning screws on a neck of the instrument.
Vertical slots 44 are formed on each end of the tailpiece 14. These slots 44 are typically rounded and extend from the top surface 42 through the bottom surface, and accommodate the tailpiece studs or posts 46 upon which the tailpiece 14 is mounted.
Many of these kinds of bridges and tailpieces of the prior art are only held in place by the tension of the strings 16 such that when the strings are removed, the bridge and tailpiece become freely removable. If proper care is not taken, the bridge, tailpiece and other components may fall off the instrument during string replacement and possible mar the instrument body or the components. Furthermore, a complete readjustment of all the components of the stringed instrument is typically required after every loosening and/or removal of strings for simple operations such as cleaning and simple maintenance, thereby necessitating considerable time and effort to return the instrument to a playable condition.
To address some of these problems with the prior art, some manufacturers of Tune-o-matic style bridges added the feature of one or more set-screws on the bridge and tailpiece, located adjacent and perpendicular to the vertical adjustment hole 26 and slot 44 respectively. The setscrew is within a threaded hole on the edge of the bridge or tailpiece, extending from the edge into the vertical adjustment hole 26 or slot 44. The setscrew is tightened against the top portion of the post member 34 in the case of a bridge, and against the tailpiece post 46 in the case of a tailpiece, to secure the respective part onto its post. A problem with the use of a setscrew is that the threads of the setscrew hole can become stripped which would necessitate replacement of the entire bridge or tailpiece. Another problem is that over tightening the setscrew causes damage to the upper portion of the post member 34, which in the case of a post having a threaded upper portion, would destroy the threads thereby limiting the range of movement of the adjustment wheel 36. A further problem is that the setscrew requires the use of another tool, such as a small sized hex key or Allen wrench, which can be lost, causing an inconvenience to the user until a replacement is found. In addition, the vertical alignment holes in the kinds of bridges often have a very slight taper as a result of the manufacturing process and the tightening of a setscrew forces the tapered internal wall of the vertical adjustment hole against the post which imparts a slight tilt to the bridge. Accordingly, there is a need for an improved devices and methods for securing a bridge and tailpiece to a stringed instrument body, such as a guitar body.